Shaft seal of a mixing and kneading machine

Abstract

A sealing arrangement is provided between the shaft of a mixing tool and the wall of a housing of a mixing and kneading machine, the sealing arrangement having a housing liner and a gland member which can be axially displaced against a support ring arranged between the shaft and the housing liner. The liner is formed by an outer sleeve sealingly placed in the wall of the housing and an inner sleeve resiliently abutted against the outer sleeve to define an annular space therebetween which is sealed by elastic seals which are pressurized by a pressure medium. A sealing arrangement of juxtaposed elastic gaskets is arranged in an annular space between the inner sleeve and the shaft and the gaskets are axially compressed between the gland member and an inward projection at the end of the inner sleeve.

What is claimed is: 
     
       1. A sealing arrangement in the bore of a housing of a mixing and kneading machine for sealing a shaft of a mixing tool in the housing, said arrangement comprising: inner and outer concentric sleeves disposed in the housing between the shaft of the mixing tool and the housing, said inner and outer sleeves defining an annular space therebetween;   means supporting said sleeves from said housing for relative axial movement between the sleeves;   elastic means sealing said annular space;   means for introducing a pressure medium into said annular space to pressurize said elastic means and provide an elastic sealing of said annular space which permits relative axial movement of said sleeves, and   further elastic means between said inner sleeve and said shaft for sealing said inner sleeve and said shaft, said inner sleeve including an annular head, said further elastic means comprising a gland member facing said annular head in axially spaced relation and a plurality of elastic gaskets clamped between said annular head and said gland member to provide a seal between said inner sleeve and said shaft.   
     
     
       2. A sealing arrangement as claimed in claim 1, wherein said elastic means comprises two axially spaced prestressing rings disposed in said annular space, said prestressing forming respective chambers with said inner and outer sleeves, and elastic sealing rings in said chambers in sealed contact with said inner sleeve, said means for introducing a pressure medium comprising a pressure connection for supply of said pressure medium between said prestressing rings to compress said elastic sealing rings in said chambers. 
     
     
       3. A sealing arrangement as claimed in claim 2, wherein said elastic sealing rings each has an annular groove therein. 
     
     
       4. A sealing arrangement as claimed in claim 2, wherein said pressure connection includes a channel in said outer sleeve extending into said annular space. 
     
     
       5. A sealing arrangement as claimed in claim 2, comprising spring means between said prestressing rings for urging said rings axially apart to compress said elastic sealing rings in said chambers. 
     
     
       6. A sealing arrangement as claimed in claim 5, comprising pins slidably engaging said prestressing rings to prevent relative turning therebetween. 
     
     
       7. A sealing arrangement as claimed in claim 1, wherein said elastic means comprises first and second coaxially arranged rings which are axially displaceable relative to one another. 
     
     
       8. A sealing arrangement as claimed in claim 7, wherein one of said coaxially arranged rings defines a first chamber with one of said sleeves and a second chamber with the other of said rings, said elastic means further comprising elastic sealing rings in said chambers in sealing contact with said inner sleeve. 
     
     
       9. A sealing arrangement as claimed in claim 8, wherein said means for introducing a pressure medium comprises a channel in said first ring communicating with one of said chambers. 
     
     
       10. A sealing arrangement as claimed in claim 9, wherein said first ring is an outer ring and said second ring is an inner ring, each of said rings including an annular radially projecting head which bounds a respective one of said chambers. 
     
     
       11. A sealing arrangement as claimed in claim 10, wherein said outer sleeve includes an annular projection extending radially of said sleeve facing the radially projecting head of the second ring to form said first chamber. 
     
     
       12. A sealing arrangement as claimed in claim 1, wherein said elastic gaskets include juxtaposed gaskets which are trapezoidal in cross-section. 
     
     
       13. A sealing arrangement as claimed in claim 12, wherein said further elastic means comprises further gaskets which are juxtaposed and axially spaced from the trapezoidal gaskets and a bearing ring of rigid material interposed between said trapezoidal gaskets and said further gaskets. 
     
     
       14. A sealing arrangement as claimed in claim 13, wherein said bearing ring has a radial bore facing said shaft, said inner sleeve having a feed bore which communicates with said radial bore in the bearing ring to supply a lubricating and sealing agent to said shaft via said radial bore. 
     
     
       15. A sealing arrangement as claimed in claim 1, wherein said inner and outer sleeves have respective ends with inclined surfaces facing into said housing. 
     
     
       16. A sealing arrangement as claimed in claim 1, wherein said means elastically supporting the sleeves from the housing comprises a first bolt connection including a spring between said housing and one of said sleeves, and a second bolt connection including a spring between said one of said sleeves and said sealing ring.